Isolated pituitary metastasis from renal cell carcinoma in a horseshoe kidney

Objective: To describe a patient with isolated symptomatic pituitary metastasis from Renal Cell Carcinoma (RCC) in a horseshoe kidney.Case report: We report a case of 56-year-old man with RCC of a horseshoe kidney with symptomatic isolated pituitary gland metastasis. He initially presented to us for evaluation of a sellar mass. He complained of fatigue, 50-pound weight loss, anorexia, constipation and nonspecific abdominal pain for 4 months. CT head showed 2.6 cm × 1.8 cm × 2.5 cm sellar mass likely with bilateral cavernous sinus extension. Pituitary function evaluation revealed panhypopituitarism. CT abdomen/pelvis for the evaluation of abdominal pain showed 12.1 cm solid mass in the right renal moiety of a horseshoe kidney. Hydrocortisone and levothyroxine therapy led to cessation of weight loss, but unmasked diabetes insipidus requiring desmopressin therapy. Right heminephrectomy confirmed RCC. Soon after he complained of progressively worsening headache and visual disturbance. Histopathology from urgent trans-sphenoidal hypophysectomy revealed RCC. The patient began post-surgical radiotherapy, but eventually he declined further treatments. In the end, he was placed on hospice where he passed away.Conclusion: Symptomatic pituitary metastasis from RCC are rare and most of those occur in the setting of diffuse metastatic disease. They typically mimic signs and symptoms of non-functioning macroadenomas. They can be synchronous, metachronous or even the presenting lesion of the primary tumor. A pituitary mass in the setting of malignancy should raise suspicion for metastatic disease even though it is extremely rare.